Photographic diffusion transfer processes employing image receiving layers containing poly-4-vinylpyridine



PROC- LAY- ERS CGNTAINING POLY- l-VINYLPYRIDINE Howard C. Haas, Arlington, Mass, assignor to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware No Drawing. Filed Aug. 22, 1960, Ser. No. 50,348

7 Claims. (Cl. 96-2 invention is to provide novel receiving elements for use in color diffusion processes.

Another object of this invention is to provide novel color diffusion transfer processes utilizing said imagereceiving elements.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description.

The present invention is particularly related to color diffusion transfer processes. In such processes a sheet of photosensitive material is exposed to create therein a latent image. image is developed and,

imagetransfer terials is transferred by processing liquid to a superposed image-receiving layer to form a colored positive image thereon. As examples of of Howard G. Rogers, Serial No. 748,421, filed July 14, 1958, wherein dye developers (i.e., dyes containing a The image-receiving elements used in such processes generally comprise an opaque or transparent support coated with an image-receiving layer of a dyeable material which is permeable to the alkaline aqueous processing It has now been discovered that by using an image receiving layer comprising a polyvinylpyridine polymer and especially a poly-4-vinylpyridine polymer, transfer images having good stability and improved density may be obtained.

The image-receiving elements of this invention are particularly useful in color diffusion transfer processes which employ dye developers. The improvements have been developing function. They may be further defined dyes which are silver halide developers. By a silver halide developing function is meant a radical capable of developing an exposed silver halide image.

a benzenoid developing radical. A preferred benzenoid developing radical in such compounds is a hydroquinonyl radical.

given in the previously mentioned U.S. Howard G. Rogers, Serial No. 748,421. Additional useful dye developers are described in the following copending [1.8. applications:

Application Serial No. 612,045, filed September 25, 1956, in the names of Elkan R. Blout, Milton Green and Howard G. Rogers.

Application Serial No. 612,052, filed September 25, 1956, in the names of Milton Green and Howard G. Rogers.

Application Serial No. 612,053, filed September 25, 1956, in the name of Myron S. Simon.

Application Serial No. 612,054, filed September 25, 1956, in the names of Helen P. Husek and Myron S. Simon.

Application Serial No. 612,055, 1956, in the name of Helen P. Husek.

Application Serial No. 755,804, filed August 18, 1958, in the names of Elkan R. Blout, Saul G. Cohen, Milton Green and Myron S. Simon.

Application Serial No. 824,785, filed July 3, 1959, in

filed September 25,

oxidized dye developer, dissolved in'the liquid processing as a function of the point-to-point degree At least part of this imagewise distribution of unoxidized is transferred, by imbibition, to a superposed imagereceiving layer or element, said transfer substantially exeluding oxidized dye developer. The image-receiving ele ment receives a depthwise diffusion, from the developed emulsion, of unoxidized dye developer without appreciably disturbing the imagewise distribution thereof to provide a reversed or positive color image of the developed image.

The novel image-receiving elements within the scope of this invention may be prepared by coating a sheet of a suitable film support such as cellulose acetate, cellulose acetate-coated baryta paper, etc., which may be suitably subcoated for proper adhesion, with a solution, preferably a 3 to solution, comprising the polyvinylpyridine polymer. Such polymers are generally not soluble in water; however, by using a small amount of acid the image-receiving layers may be cast from aqueous solutions. In a preferred embodiment, volatile acids such, for example, as formic, acetic, etc., are used in applying the coatings. Evaporation of such volatile acids after the image-receiving layer is cast renders said image-receiving layer less water sensitive. The coating and drying operations involved may be carried out by methods commonly employed in the art. The polyvinylpyridine polymer may comprise the sole dyeable film-forming material in the image-receiving layer or it may be added to other image receiving materials, e.g., gelatin, polyvinyl alcohol, etc. Especially useful results have been obtained when the polyvinylpyridine polymers are used in combination with polyvinyl alcohol. When the polyvinylpyridine polymers of this invention are used in combination with other image-receiving materials the ratio of the polyvinylpyridine polymer to the other image-receiving materials may be varied to suit particular needs. Especially good results have been obtained if the polyvinylpyridine polymers comprise 10 to 100% of the dyeable film-forming materials, with the broadest range being suitable, where polyvinyl alcohol is used.

The term polyvinylpyridine polymers" as used herein refers to polymers which comprise a major portion of vinylpyridine segments and more preferably to homopolymers of a vinylpyridine. As mentioned above, vinylpyridine polymers have been found particularly useful. Such 4-vinylpyridine polymers provide transfer images which are substantially denser than those produced on poly-Z-vinylpyridine image-receiving layers.

The polyvinylpyridine polymers for use in the imagereceiving layers of this invention may be prepared by polymerization techniques well known to the art. The following example illustrates the preparation of a polyvinylpyridine polymer for use in the image-receiving layers of this invention.

EXAMPLE 1 50 grns. of 4-vinylpyridine, 0.63 gm. of benzoyl peroxide and 0.5 gm. of a 25% aqueous solution comprising 0.912 gm. of hide glue and 0.034 gm. of Nekal BA-75 (trade name of General Dyestufi Corporation, N,Y., N.Y., for a sodium alkyl naphthalene sulfonate), were placed in 100 cc. of distilled water and polymerized for 2 hours at 50 C. under nitrogen, using a high speed stirrer. The resulting mixture was poured into 3 liters of Water and the polymeric precipitate was filtered and washed with an excess of water. The polymer was dried under vacuum at 30 C.

The following non limiting examples illustrate the preparation of image-receiving elements within the scope of this invention.

EXAMPLE 2 A sheet of subcoated baryta paper was coated with an aqueous solution containing a small amount of acetic acid and comprising:

Percent Elvanol 72-60 (trade name of E. I. du Pont de Nemours & Co., Wilmington, Delaware for high viscosity, 100% hydrolyzed polyvinyl alcohol) 2.4 Poly-4-vinylpyridine 2.4 l-phenyl-S-mercaptotetrazole 0.08

4 EXAMPLE 3 EXAMPLE 4 An image-receiving element was prepared as in Example 2 except that the aqueous coating solution comprised acetic acid and:

Percent Elvanol 72-60= 3.6 Poly-4-vinylpyridine 1.2 1-phenyl-S-mercaptotetrazole 0.08

EXAMPLE 5 A sheet of subcoated baryta paper was coated with an aqueous solution comprising:

Percent Gelatin 2.25 Poly-4-vinylpyridine 2.25 Saponin 0.22 Formaldehyde 0.015 1-phenyl-5-mercaptotetrazole 0.098

EXAMPLE 6 An image-receiving element was made up as in Example A control image-receiving sheet was prepared by coating a subcoated baryta paper with an aqueous solution comprising:

Percent Elvanol 72-60 4.8 Sodium perborate 0.01 l-phenyl-S-mercaptotetrazole 0.08

and a few drops of a nonionie wetting agent.

The image-receiving elements prepared in the above examples, along with the polyvinyl alcohol control, were tested in diffusion transfer processes by using them in processes employing multilayer photosensitive elements prepared in a manner similar to that disclosed in the above-mentioned copending application Serial No. 748,- 421. In general, the photosensitive elements comprised a support carrying a red-sensitive silver halide emulsion stratum, a green-sensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum; said emulsion having disposed in separate alkali-permeable layers behind them, respectively, a cyan dye developer, a magneta dye developer and a yellow dye developer. The particular dye developers employed in the photosensitive elements were (1) 1,4-bis-[a-methyl-B-(2,5'-dihydroxyphenyl) ethylamino]-5,8-dihydroxyanthraquinone (a cyan dye developer), (2) 2-[p-(2',5'-dihydroxyphenethyl)-phenylazo]-4-propoxy-1-napbthol (a magneta dye developer) and (3) l-phenyl-3-n-hexyl carboxarnidoi- [p-(hydroquinonylethyl)-phenylazo1-5-pyrazolone (a yellow dye developer).

In conducting the test, areas of the photosensitive elements were exposed to (1) blue and green light only, (2) red and blue light only, (3) red and green light only, (4) totally exposed and (5) subjected to no exposure. After the transfer process, the integral densities in each of these areas were measured by reflectance using red, green and blue filters.

The results, appearing in tabular form below, indicate the improved density obtained using the image-receiving elements of this invention.

POLYVINYL ALCOHOL CONTROL OF EXAMPLE 7 Density Exposure Red filter Green filter Blue filter Blue and green -i 1. 17 0. 46 0. 31 Red and blue 0. 12 0.79 0. 50 Red and green 0.09 0. 17 0.95 Total exposure 0.05 0.08 0. No exposure 1. 22 1. 24 l. 65

IMAGE RECEIVING ELEMENT OF EXAMPLE 2 Blue and green- Red and blue--. Red and green Total exposure N 0 exposure Ih/IAGE-REOEIVING ELEMENT OF EXAMPLE 3 Blue and green Red and blue Red and green Total exposure... N 0 exposure IMAGE-RECEIVING ELEMENT OF EXAMPLE 4 Blue and green 1 57 0.69 0 Red and blue 0 09 0.98 0 Red and green 0 03 0.28 1 Total exposure 0 08 0. 12 0 IMAGE-RECEIVING ELEMENT OF EXAMPLE 6 Blue and green 0. 73 0. 39 0.29 Red and blue 0. 11 0. 90 0.58 Red and green.-- 0. 04 0. 16 1. 30 Total exposure--. 0. 07 0. 09 0. 12 N 0 exposure 0 66 1. 42 2. 12

When the polyvinylpyridines are used in combination with water-sensitive polymers, such, for example, as polyvinyl alcohol, it is preferable to also employ reagents such as hardeners, cross-linking agents, and other reagents which will reduce the water-sensitivity of the resulting layer.

The transfer images produced on the image-receiving element of this invention, in addition to having improved density, also possess improved brightness and gloss as compared to transfer images produced on polyvinyl alcohol alone.

The image-receiving elements of this invention are an image-receiving element and a rupturable pod containing an aqueous alkaline processing solution. The elements and pod are so associated with each other that, upon processing, the photosensitive element may be superposed on the image-receiving element and the pod may be ruptured to spread the aqueous alkaline It should be noted that other materials useful in the diifusion transfer processes may be incorporated into the image-receiving layer. As examples of such materials, mention may be made of dye mordants, antifoggants, oxidizing agents, and acids and alkalies for pH adjustments.

illustrative and not in a limiting sense.

What is claimed is: 1. In a process of forming a photographic image in receiving layer in superposed relationship with said emulsaid image-receiving layer a reversed of the developed image, the step of transferring said distribution of unoxidized dye developer to an image-receiving layer comprising poly-4-vinylpyridine.

2. A process as defined receiving layer comprises 4-vinylpyridine.

3. A process as defined in claim 2 wherein the ratio of poly-4-vinylpyridine to gelatin is 1 to 1 on a weight basis.

in claim 1 wherein said imagegelatin in addition to said polyreceiving layer comprises said poly-4-vinylpyridine.

5. A process as defined in claim 3 wherein the ratio of said poly-4-vinylpyridine to polyvinyl alcohol in said image-receiving layer is about 1 to 2 on a 6. A process as defined in claim 1 developer is an azo dye developer.

7. A process as defined in claim 1 wherein said dye developer is an anthraquinone dye developer.

References Cited in the file of this patent UNITED STATES PATENTS 2,448,542 McQueen Sept. 7, 1948 2,448,552 Schulze Sept. 7, 1948 2,548,564 Sprague et a1 Apr. 10, 1951 2,548,575 Weyerts Apr. 10, 1951 2,564,726 Saner Aug. 21, 1951 2,798,063 Fowler July 2, 1957 2,830,900 Land et a1. Apr. 15, 1958 2,868,077 Ryan et a1 Jan. 13, 1959 2,983,606 Rogers May 9, 1961 FOREIGN PATENTS 577,021 Canada June 3, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,148,061 September 8, 1964 Howard C. Haas It is hereby certified that'error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. Y

Column 2, line 20, after "748,421" insert (now U.S. Patent No. 2,983,606, issued May 9-, 1961) line 25, after "Rogers" insert (now abandoned and replaced by application Serial No. 144,816, filed October 18', 1961) line 28, after "Rogers" insert (now abandoned and replaced by application Serial No. 165,940, filed January 12, 1962) line 30, after "Simon" insert (now abandoned and replaced by application Serial No. 196,523, filed May 21, 1962) line 33, after "Simon" insert (now abandoned and replaced by applications Serial Nos. 197,259 and 197,283, filed May 24, 1962) after "Husek" insert (now abandoned and replaced by applications Serial Nos. 192,354 and 192,355, filed May 4, 1962) line 38, after "Simon" insert (now abandoned) line 41, after "Woodward" insert (now abandoned and replaced by application Serial No. 233,461, filed October 26, 1962) same column 2, line 43, after "Simon" insert (now abandoned) column 3, line 54, for "0.912" read 0.0913 column 4, line 33, for "Polyvinyl4-vinylpyridine" read Poly-4-viny1- pyridine line 51, after "421" insert (now U.S. .Patent No. 2,983,606, issued May 9, 1961) same column 4, line 57, for "magneta" read magenta column 6, line 45, for the l i reference numeral "3" read 4.; line 67, for "June 3, 1959" read June 2, 1959 Signed and sealed this 26th day of October 1965.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents line 35 

1. IN A PROCESS OF FORMING A PHOTOGRAPHIC IMAGE IN COLOR, WHEREIN A LATENT IMAGE CONTAINED IN AN EXPOSED SILVER HALIDE EMULSION IS DEVELOPED IN THE PRESENCE OF A DYE DEVELOPER, SAID DYE DEVELOPER BEING A COMPOUND WHICH IS BOTH A DYE AND A SILVER HALIDE DEVELOPER, TO PROVIDE IN SAID EMULSION A PREDETERMINED DISTRIBUTION OF UNOXIDIZED DYE DEVELOPER AND WHEREIN AT LEAST A PORTION OF SAID DISTRIBUTION OF SAID UNOXIDIZED DYE DEVELOPER IS TRANSFERRED BY INBIBTION FROM SAID EMULSION TO AN IMAGERECEIVING LAYER IN SUPERPOSED RELATIONSHIP WITH SAID EMULSION TO IMPART TO SAID IMAGE-RECEIVING LAYER A REVERSED POSITIVE DYE IMAGE OF THE DEVELOPED IMAGE, THE STEP OF TRANSFERRING SAID DISTRIBUTION OF UNOXIDIZED DYE DEVELOPER TO AN IMAGE-RECEIVING LAYER COMPRISING POLY-4-VINYLPYRIDINE. 